1. Field of the Invention
This invention relates to the prophylactic or therapeutic treatment of periodontal disease, which is a gum disease.
2. Description of the Prior Art
The term "periodontal disease" as used herein includes any inflammatory disease of the periodontium (tooth-surrounding tissue). It is the most widespread human ailment affecting, to varying degrees of severity, the entire population. Chronic inflammatory periodontal disease (CIPD) is the major cause of tooth loss in adults. CIPD is the direct result of the accumulation of dental plaque between the "gum" and the tooth, i.e. in the gingival crevice. The microflora of this plaque is extremely complex, more than 250 component bacterial species having been described. It is not certain which of them cause the disease. There is, however, one point on which all investigators agree: the flora of the healthy gingival sulcus is sparse and consists largely of aerobic and facultative Gram-positive bacteria, while in the diseased state, when the sulcus becomes a crevice or pocket, there is a pronounced increase in the proportion of anaerobic and microaerophilic bacteria: Loesche et al, Journal of Periodontology 56, 447-456 (1985) and M. G. Newman, Journal of Periodontology 56, 734-739 (1985). The proportion of anaerobes increases with the severity of the disease. Those of the genus Bacteroides are considered to be among the important pathogens.
Attempts have been made to combat CIPD by preventing or reversing this increase in the proportion of anaerobic bacteria in the gingival crevice by removing the plaque, a tedious, labour-intensive and time-consuming process; by using antiseptics or antibiotics, an inadvisable course since it invariably leads to the development of a resistant microflora; or by applying to that locus a molecular oxygen-supplying substance, for example chromic acid; potassium permanganate; sodium peroxyborate; sodium perborate; calcium hypochlorite; zinc peroxide; urea peroxide; hydrogen peroxide; or molecular oxygen itself.
Of the oxygen-supplying substances only hydrogen peroxide remains in clinical use; and the efficacy of this use is a source of controversy in the dental profession. The failure of this group of compounds to treat the disease effectively might be due to the transience of oxygen provision in the periodontal pocket, allowing the rapid re-establishment of an anaerobic environment and the consequent growth of the pathogenic anaerobes. In addition, these highly-reactive compounds are likely to damage the tissues of the periodontium and possibly aggravate the inflammation.
Specific prior art relating to the invention is referred to in a separate section following the "Summary of the invention", without which its relationship would not be apparent.
If the current enormous cost of restorative treatments for dental caries is not to be paralleled by similarly expensive periodontal surgery, applied to large sections of the population, less costly and more effective means of prevention and control of periodontal disease need to be developed.